A program of laboratory and observational studies is proposed to examine normal changes from middle childhood to adolescence. A basic premise of the proposed studies is that rapid cognitive, socioemotional, and physical changes in the child and concurrent psychosocial issues faced by parents result in distortions of interpersonal perceptions and attributions. These in turn may lead to conflict, dysfunctional or ineffective responses, and personal and interpersonal stress. Research to date had demonstrated that: adults typically hold differentiated expectations for behavior during the preadolescent and early-adolescent period; physical maturity and age elicit particular behavioral expectations; children's assessments of parental influence strategies are influenced by age-related concepts of parent-child relations. In the proposed continuation period, interpersonal implications of changing expectations will be examined. Cross-sequential observational studies will be executed to trace changes in behavior, expectations, and family functioning in families with oldest children between the ages of 10 and 16. Methods include in situ and structured laboratory interaction tasks, interviews, and standardized measures of personality and family functioning will be included. Social-structural variables (e.g., social class, number of parents in the home, age of parents) will be restricted by the sampling methods in the first phase of the research in order to focus on basic psychological and interpersonal processes, but these variables will be examined in subsequent work. In order to clarify and test the cross-situational validity of findings, these studies will be conducted in oscillation with experimental studies of basic social-cognitive and interpersonal processes. Results should provide a basis for identifying potential ways in which parents and mental health and other professionals may help adolescents and families cope adaptively with stresses of the transition into adolescence.